What led Israel through the wilderness for forty years?
The cloud and the pillar of fire led Israel throughout the forty years of wilderness journeys in Sinai. From the time they came out of Egypt onward, that cloud and pillar were evident as their leading force, guiding the children of Israel until the time described in Joshua, when the Ark of the Covenant carried by priests led them instead.
Les explains that when Israel came out of Egypt, the first thing that appeared to lead them was the cloud or pillar of fire. Throughout all forty years of their wilderness journeys in Sinai, that cloud and pillar of fire remained evident and was their leading force. Later, at the Jordan in Joshua chapter 3, the leadership changes: it is not the cloud that leads them into the river, but the Ark of the Covenant carried by the priests.